The objective of this study is to evaluate the effect of ORTHO TRI-CYCLEN on the biochemical markers of bone resporption (Deoxypyrodinoline, N-telopeptide) and formation (Bone Specific Alkaline Phosphatase, Osteocalcin, Procollagen of Type I Propeptide (P-I-CP) in women with hypothalamic amenorrhea and osteopenia secondary to their condition. A second objective is to evaluate the effect of ORTHO TRI-CYCLEN on cognitive function. The first phase of the protocol is a three month randomized, placebo-controlled prospective study of the effects of oral contraceptives on bone turnover in women with hypothalamic amenorrhea. The primary endpoints of this study are bone resorption markers (N-telopeptide and deoxypyridinoline) and bone formation markers (osteocalcin, bone specific alkaline phosphatase and PICP). Secondary endpoints include include cognitive function testing, weight and body composition, as measured by skin fold analysis. The second phase of this protocol is a nine month open label extension of the above protocol in which all subjects who wish to continue receive oral contraceptives. The primary endpoint is the effect of oral contraceptives on bone density as measured by Dual Xray Absorpiometry (DXA).